Will avionics makers be ready for inauguration of IFR WAAS?

 - May 9, 2008, 5:57 AM

The recent successful completion of a 60-day continuous performance test of the FAA’s wide-area augmentation system (WAAS) is expected to clear the way for full IFR use of the satellite navigation concept starting late next year. The question now is whether anyone will be able to use it.

While pilot groups and avionics makers  applaud the news, the manufacturers appear to have been caught somewhat flat-footed by the unexpected announcement from the FAA that the beleaguered WAAS program is moving forward and not backward.

As a result, few companies anticipate bringing WAAS-certified IFR equipment to market in time for the debut of IFR capability, now expected next fall. The soonest any of the large established manufacturers anticipate completing certification of IFR WAAS equipment is sometime in 2004. What that likely means for the program is WAAS routes and precision approaches will be available, but few if any pilots will be able to take advantage of them.

The lapse by avionics manufacturers should not come as a complete surprise. The program has experienced so many setbacks in the last decade that no one, not even FAA planners, could realistically predict when WAAS would fully come online.

The main space portion of WAAS consists of a pair of satellites that continuously calculate the error of GPS satellites, as well as the error induced by the atmosphere and any errors in the satellite’s atomic clocks. The geostationary satellites (one over the eastern U.S. and a second covering the West) then transmit signals to WAAS-capable GPS receivers, telling them precisely what those errors are. These signal corrections provide greater accuracy than GPS alone, thereby allowing satellite precision approaches to Cat I minimums.

In the GA market, the race to watch is between Honeywell Bendix/King and Garmin. Both report having begun development of WAAS-compatible IFR panel-mount avionics. The first products are expected to become available by spring 2004, after which a flood of new equipment is anticipated. But makers are keeping quiet for the time being. Their reticence can be attributed to the fact that none wants to tip its hand too early and reveal what functionality will be included with initial WAAS IFR boxes or at what price.

Observers speculate that Bendix/King and Garmin are both planning WAAS IFR-capable versions of their popular GA multifunction lines, namely the Bendix/King IHAS and Garmin GNS 430/530, as well as completely new WAAS-enabled products. Eventually, WAAS IFR capability will be brought to all manner of cockpit avionics, from GA panel-mount hardware to full avionics systems for business jets.

Anatomy of a ‘Boondoggle’

The snags that have held up the troubled WAAS program since its inception in 1992 are well documented. During the first top-level review of WAAS in 1994, when the first signs of trouble were just starting to rear their heads, the FAA predicted Cat I service throughout about half the country would be available by 1997, with full coverage by 2000. Four years later–after much of the early optimism had faded and the hardware and communications problems were more fully understood–the 50-percent forecast had slipped by two years to 1999, with 100-percent coverage promised by 2001. Then, in 1999, the 50-percent projection drifted further to 2000, and full coverage was shifted out to 2007.

In 2000, in the wake of a number of high-profile schedule slippages and cost overruns (WAAS failed the 60-day integrity test early that year, triggering a three-year delay), Congress was growing impatient with the lack of progress being made by government planners. At a June 2000 Transportation Committee hearing, members of Congress openly questioned the FAA’s management of the overbudget, behind-schedule satellite navigation system, with one Republican Congressman, Rep. John Mica of Florida, summing up his frustration by calling WAAS a monumental waste of money.

“I used to worry that this program would become a billion-dollar boondoggle,” Mica said during the aviation subcommittee debate. “Now, it looks like WAAS is well on its way to becoming a $4 billion boondoggle.”

Mica’s memorable remark stuck, becoming emblematic of Congress’ growing irritation with the FAA on the subject of big-ticket modernization programs. For WAAS and those within the FAA who had staked their reputations on the concept, the future was looking dim.

But then last year there was some good news for a change. The WAAS signal was made available for VFR use, a significant positive milestone for a program that at one time seemed perilously close to being canceled altogether. Behind the scenes, FAA officials had their fingers crossed that there would be no more unpleasant surprises.

The real irony in the last few years has been that WAAS has been demonstrated to work well–just not well enough. The latest 60-day integrity test further validates the concept and, in fact, is one of the few remaining hurdles before WAAS can be deployed for IFR en route and approach use. Assuming no major flaws are discovered in the next 12 months, it appears increasingly likely that the WAAS story will have a happy ending after all.

FAA planners wish the same could be said for the local-area augmentation system (LAAS), now coming under fire for its high cost. Unlike WAAS, LAAS relies on ground stations positioned around airports to augment GPS signals, providing even greater accuracy than WAAS, but in a relatively small area. While WAAS promised Cat I capability, LAAS was supposed to have opened the doors for full Cat II/III landings, replacing ILS as the precision landing aid of the future.

LAAS had always seemed the innocent stepchild, enduring little of the negative attention WAAS had. Yet now the FAA is trying to determine whether there really is a firm need for LAAS, especially in light of recent decisions to design and implement required navigation performance (RNP) techniques for precision landings (see above story).

There really is nothing fundamentally wrong with LAAS, it’s just that some within the FAA are beginning to think there may be a better and less expensive way to get the same results.

The agency announced in October that RNP approach procedures will be implemented at San Francisco International Airport to allow IMC approaches to the airport’s closely spaced parallel runways.

Similar approaches are already in use by Alaska Airlines at Juneau Airport, where they allow curved tracks to landing to avoid nearby mountains.

Boeing, a company that in recent years has put a lot of its eggs in the airspace-management basket, has floated a proposal to replace 18 different types of instrument approaches with a single, ILS-like procedure based on RNP.